1. Field of Invention.
This invention is in the general area of wheeled vehicles. In particular, the axle-frame alignment system, suspension system, steering system and steering drive axle are involved in the invention.
2. Background of the invention.
Wide stance suspension systems have been previously known, Daimler Benz, French Pat. No. 997.430. In previous systems, scuffing of tires in turns could not be prevented. In addition, the axles would "walk", a converse fore and aft motion, and have other motions which were uncontrolled. This invention overcomes that problem by the use of the double wishbone.
In normal suspension systems, torque arms, stabilizer bars, and/or spring shackles restrain the axle in its correct transverse alignment to the frame. If any vertical motion of the vehicle is not simultaneous at both ends of an axle, the restraining parts pull the axle out of alignment with the frame and cause a change in the direction of travel, called "wander", which is corrected by turning the steering wheels. All the foregoing components, by necessity, have joints under severe tension, and are thus prone to wear and failure.
This invention separates the suspension system from the axle-frame alignment system to ensure that both systems are more effective.
The telescoping wishbone of my invention maintains the transverse center of the axle directly on the vertical centerline of the vehicle at all times while the sold wishbone prevents forward and backward motion at the ends of the axle, keeping the whole in exact alignment with the frame. With all axles of a vehicle having their respective balls and sockets at the same vertical height from ground level, tension and wear on all alignment components are reduced. Stress is also reduced because the alignment components bear none of the weight of the vehicle and the suspension components bear none of the torsion. Furthermore, drag or road friction caused by misaligned axles, particularly misaligned dual axles, is reduced because each axle is aligned with the frame.
Wide stance suspension similar to the Daimler-Benz patent lends greater stability to a vehicle while providing for a softer ride because it eliminates the fulcrum point on the axles inboard of the tires. With normal suspension systems, springs, pads, or air bags are mounted between the frame and axles inboard of the wheels which constitutes fulcrum points over which the weight of the vehicle pivots. For every action there is an equal and opposite reaction, therefore, for every motion at the end of an axle, the opposite end reacts negatively, contributing to each bounce communicated to the frame. Also, the overhang on each side from the spring to the side of the vehicle carries weight that contributes to the undesirable tendency for the vehicle to pivot on its spring and roll over. This tendency is increased when the vehicle is already leaning, as in turns, because the overall center of gravity of the vehicle is considerably higher than the axle and it shifts from side to side depending upon the lean of the vehicle. With air bags or springs located at a vehicle's extreme width, these tendencies are overcome.
When vehicles with dual drive axles turn, the tires not on the exact turning radius are forced to slide which causes tire wear and breaks road surface contact or traction. The greater distance conventional dual drive axles are separated, the greater the disadvantages of tire wear and loss of traction. Under this system, all tires have the same turning radius, hence low wear and greater traction. Also, with the same radius for both front and rear drive axles, there is less strain on the inter-axle differential, which is the device that compensates for the axles travelling at different speeds as would be necessary if they had different turning radii or different size tires.
If the longitudinal center of balance of the load is near the center of the dual drive rear axles, a bucking motion can occur. With each bounce on rough roads, the center of balance moves back and then forward and, once begun, seems to perpetuate like a pendulum. To overcome this problem, it is desirable to separate the dual drive axles as far apart as is practical to better distribute the load for the same reason as placing the suspension parts at the extreme width of the vehicle for stability. With this invention drive axles can be separated much further apart.
Steering drive axles in use today transmit power through the steering knuckle by means of the conventional universal joint. Such joint has vibration at all angles of turning except a very small range. The parts of the universal joint are small because they must fit within the confines of the steering knuckle unit which likewise must fit within the wheel itself. This invention replaces the universal joint with a power pivot that will run smoothly with no vibration and has fewer and larger parts for more strength.
With the advent of longer-wider trailers, some highways and urban streets are too crooked or intersections too narrow for these trailers to negotiate. Normal trailers steer towards the hitch on the forward vehicle. Therefore, they cut toward the inside of every turn in direct relation to the length from the hitch to the rear wheels.
This invention's steering trailer steers toward the outside of the turn in an amount determined by the angle of the forward vehicle in relation to the trailer. An advantage of this system is that, except for the requirements of a notch cut in the side of a conventional tractor fifth wheel, all the parts of this system are permanently attached to the trailer and can be locked in straight-ahead position if steering is not required or a conventional tractor fifth wheel is used.